Fiber optic connectors of a wide variety of designs have been employed to terminate optical fiber cables and to facilitate connection of the cables to other cables or other optical fiber transmission devices. A typical fiber optic connector includes a ferrule which mounts and centers an optical fiber or fibers within the connector. The ferrule may be fabricated of such material as ceramic. A ferrule holder or other housing component of the connector embraces the ferrule and may be fabricated of such material as molded plastic. A spring typically is disposed within the housing or ferrule holder such that the ferrule is yieldably biased forwardly for engaging another fiber-mounting ferrule of a mating connector device. Some fiber optic connectors allow for angular adjustment of the optical fiber within the connector to achieve an optimum angular position of the fiber whereat the insertion losses of the connector are at a minimum. For instance, indexing means may be provided within the connector to define and hold the fiber-terminating ferrule in any one of a plurality of rotational positions. During or after assembly, the ferrule is rotated from one position to another sequentially, with the insertion losses measured at each position. When the optimum position is determined, the ferrule is assembled in the optimum position of adjustment, and the connector is ready for mating with a complementary connector or other fiber transmission device. In other connectors, the optimum angular position or orientation is achieved by polishing the end face of the ferrule and the optical fiber terminated therewithin.
A problem continues to be encountered with adjustable fiber optic connectors as described above. Specifically, after termination of the fiber within the connector, and after the optimum angular position of the fiber-terminating ferrule is determined, or the end face of the ferrule and fiber are polished, the ferrule and fiber often are accidentally rotated away from the optimum angular position thereof, as described above. This typically occurs because of the spring loading of the ferrule or ferrule holder, whereby the ferrule can he accidentally pushed inwardly against the spring forces and accidentally rotated out of or away from the optimum rotational position of adjustment. The present invention is directed to a system which prevents this type of accidental change in the angular position of the optical fiber within the fiber optic connector.